Dredging bottlenecks lakes Krommenie

What will happen?

Starting in September 2023, contractor J.P. Schilder of Ursem will begin preparations for dredging bottlenecks in Lakes Krommenie in the rural area on the border between the municipality of Zaanstad (Krommenie) and Uitgeest. The work is being commissioned by Hoogheemraadschap Hollands Noorderkwartier.

Where does the project take place?

There are a number of bottlenecks in Lakes Krommenie. The lakes are located both in the rural area of municipality Zaanstad and municipality Uitgeest and are located between the Alkmaardermeer on the north side and the provincial road N8 on the south side. The lakes (Crommenije Noord, Crommenije Zuid, Noorderham and Zuiderham) are connected by watercourses. This is also largely where the dredging bottlenecks are located. Surveys have shown that a number of sections do not meet the required height. The drawing, which you can download at the bottom of the page, shows the locations we will be dredging. 

In total, we will remove approximately 26,000^{m3 of} dredged sludge from the 4 lakes. The destination of the dredged sludge has been divided into 4 sub-streams:

• approx. 920^{m3 of} dredging sludge we dispose of to a controlled depot of Baggerzorg due to its quality.
• Approximately 2,000^{m3 of} dredging sludge we dispose of to our local depots in the area
• approximately 15,500^{m3 of} dredged sludge we salvage in a pasture depot on a plot located adjacent to the lakes.
• approximately 7,700^{m3 of} dredged sludge we are securing behind 3 nature-friendly banks (NVO) that we are constructing in the lakes. The NVOs consist of rows of piles linked together by purlins. We are constructing them to restore the erosion of banks that took place in the past.   

A dredge dredger transports the dredged material via a discharge pipeline to the meadow depot or behind the nature-friendly banks. We sink most of the discharge pipeline to minimize inconvenience to recreational boaters. The dredged sediment that goes to the depots is excavated with a crane on a pontoon and then removed by truck. 

By March 2024, the dredging work will be completed. Once the filling of the pasture depot with dredged sludge is completed, we will dewater the depot and then the sludge will mature into usable soil. Then flattening of the quays will take place and we will restore the situation to its former state by sowing the plots with grass seed. 

During the work, there is a chance that the dredging will cause temporary inconvenience to waterway traffic. We ask for your understanding. When it is of interest to local residents, we will send out a notification of the work.

When will the project take place and how long will it take?

Work will begin from September 2023 and be completed by March 2024. Decommissioning of the pasture depot is expected to take until the end of 2025. 

Who do we work with?

We are working with contractor J.P. Schilder from Ursem. Daily supervision of the work is provided by Mr. B. Slagter of the Water Board. 

Contact details for more information?

For questions, please contact Mr. N. Roskam of the Water Board via our contact form or by calling 072 - 582 8282.